ccea66710c
This PR provides a faster algorithm for converting 8-bit and 24-bit colors into the 4-bit legacy values that are required by the Win32 console APIs. It also fixes areas of the code that were incorrectly using a simple 16-color conversion that didn't handle 8-bit and 24-bit values. The faster conversion algorithm should be an improvement for issues #783 and #3950. One of the main points of this PR was to fix the `ReadConsoleOutputAttribute` API, which was using a simplified legacy color conversion (the original `TextAttribute:GetLegacyAttributes` method), which could only handle values from the 16-color table. RGB values, and colors from the 256-color table, would be mapped to completely nonsensical values. This API has now been updated to use the more correct `Settings::GenerateLegacyAttributes` method. But there were also a couple of other places in the code that were using `GetLegacyAttributes` when they really had no reason to be working with legacy attributes at all. This could result in colors being downgraded to 4-bit values (often badly, as explained above), when the code was already perfectly capable of displaying the full 24-bits. This included the fill colors in the IME composer (in `ConsoleImeInfo`), and the construction of the highlighting colors in the color search/selection handler (`Selection::_HandleColorSelection`). I also got rid of some legacy attribute code in the `Popup` class, which was originally intended to update colors below the popup when the settings changed, but actually caused more problems than it solved. The other major goal of this PR was to improve the performance of the `GenerateLegacyAttributes` method, since the existing implementation could be quite slow when dealing with RGB values. The simple cases are handled much the same as they were before. For an `IsDefault` color, we get the default index from the `Settings::_wFillAttribute` field. For an `IsIndex16` color, the index can just be returned as is. For an `IsRgb` color, the RGB components are compressed down to 8 bits (3 red, 3 green, 2 blue), simply by dropping the least significant bits. This 8-bit value is then used to lookup a representative 16-color value from a hard-coded table. An `IsIndex256` color is also converted with a lookup table, just using the existing 8-bit index. The RGB mapping table was calculated by taking each compressed 8-bit color, and picking a entry from the _Campbell_ palette that best approximated that color. This was done by looking at a range of 24-bit colors that mapped to the 8-bit value, finding the best _Campbell_ match for each of them (using a [CIEDE2000] color difference calculation), and then the most common match became the index that the 8-bit value would map to. The 256-color table was just a simpler version of this process. For each entry in the table, we take the default RGB palette value, and find it's closest match in the _Campbell_ palette. Because these tables are hard-coded, the results won't adjust to changes in the palette. However, they should still produce reasonable results for palettes that follow the standard ANSI color range. And since they're only a very loose approximation of the colors anyway, the exact value really isn't that important. That said, I have tried to make sure that if you take an RGB value for a particular index in a reasonable color scheme, then the legacy color mapped from that value should ideally match the same index. This will never be possible for all color schemes, but I have tweaked a few of the table entries to improve the results for some of the common schemes. One other point worth making regarding the hard-coded tables: even if we wanted to take the active palette into account, that wouldn't actually be possible over a conpty connection, because we can't easily know what color scheme the client application is using. At least this way the results in conhost are guaranteed to be the same as in the Windows Terminal. [CIEDE2000]: https://en.wikipedia.org/wiki/Color_difference#CIEDE2000 ## Validation Steps Performed This code still passes the `TextAttributeTests` that check the basic `GetLegacyAttribute` behaviour and verify the all legacy attributes roundtrip correctly. However, some of the values in the `RgbColorTests` had to be updated, since we're now intentionally returning different values as a result of the changes to the RGB conversion algorithm. I haven't added additional unit tests, but I have done a lot of manual testing to see how well the new algorithm works with a range of colors and a variety of different color schemes. It's not perfect in every situation, but I think it works well enough for the purpose it serves. I've also confirmed that the issues reported in #5940 and #6247 are now fixed by these changes. Closes #5940 Closes #6247 |
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Welcome to the Windows Terminal, Console and Command-Line repo
This repository contains the source code for:
- Windows Terminal
- Windows Terminal Preview
- The Windows console host (
conhost.exe) - Components shared between the two projects
- ColorTool
- Sample projects that show how to consume the Windows Console APIs
Related repositories include:
- Windows Terminal Documentation (Repo: Contribute to the docs)
- Console API Documentation
- Cascadia Code Font
Installing and running Windows Terminal
👉 Note: Windows Terminal requires Windows 10 1903 (build 18362) or later
Microsoft Store [Recommended]
Install the Windows Terminal from the Microsoft Store. This allows you to always be on the latest version when we release new builds with automatic upgrades.
This is our preferred method.
Other install methods
Via GitHub
For users who are unable to install Terminal from the Microsoft Store, Terminal builds can be manually downloaded from this repository's Releases page.
⚠ Note: If you install Terminal manually:
- Be sure to install the Desktop Bridge VC++ v14 Redistributable Package otherwise Terminal may not install and/or run and may crash at startup
- Terminal will not auto-update when new builds are released so you will need to regularly install the latest Terminal release to receive all the latest fixes and improvements!
Via Windows Package Manager CLI (aka winget)
winget users can download and install the latest Terminal release by installing the Microsoft.WindowsTerminal package:
winget install --id=Microsoft.WindowsTerminal -e
Via Chocolatey (unofficial)
Chocolatey users can download and install the latest Terminal release by installing the microsoft-windows-terminal package:
choco install microsoft-windows-terminal
To upgrade Windows Terminal using Chocolatey, run the following:
choco upgrade microsoft-windows-terminal
If you have any issues when installing/upgrading the package please go to the Windows Terminal package page and follow the Chocolatey triage process
Project Build Status
| Project | Build Status |
|---|---|
| Terminal | |
| ColorTool |
Terminal & Console Overview
Please take a few minutes to review the overview below before diving into the code:
Windows Terminal
Windows Terminal is a new, modern, feature-rich, productive terminal application for command-line users. It includes many of the features most frequently requested by the Windows command-line community including support for tabs, rich text, globalization, configurability, theming & styling, and more.
The Terminal will also need to meet our goals and measures to ensure it remains fast and efficient, and doesn't consume vast amounts of memory or power.
The Windows Console Host
The Windows Console host, conhost.exe, is Windows' original command-line user experience. It also hosts Windows' command-line infrastructure and the Windows Console API server, input engine, rendering engine, user preferences, etc. The console host code in this repository is the actual source from which the conhost.exe in Windows itself is built.
Since taking ownership of the Windows command-line in 2014, the team added several new features to the Console, including background transparency, line-based selection, support for ANSI / Virtual Terminal sequences, 24-bit color, a Pseudoconsole ("ConPTY"), and more.
However, because Windows Console's primary goal is to maintain backward compatibility, we have been unable to add many of the features the community (and the team) have been wanting for the last several years including tabs, unicode text, and emoji.
These limitations led us to create the new Windows Terminal.
You can read more about the evolution of the command-line in general, and the Windows command-line specifically in this accompanying series of blog posts on the Command-Line team's blog.
Shared Components
While overhauling Windows Console, we modernized its codebase considerably, cleanly separating logical entities into modules and classes, introduced some key extensibility points, replaced several old, home-grown collections and containers with safer, more efficient STL containers, and made the code simpler and safer by using Microsoft's Windows Implementation Libraries - WIL.
This overhaul resulted in several of Console's key components being available for re-use in any terminal implementation on Windows. These components include a new DirectWrite-based text layout and rendering engine, a text buffer capable of storing both UTF-16 and UTF-8, a VT parser/emitter, and more.
Creating the new Windows Terminal
When we started planning the new Windows Terminal application, we explored and evaluated several approaches and technology stacks. We ultimately decided that our goals would be best met by continuing our investment in our C++ codebase, which would allow us to reuse several of the aforementioned modernized components in both the existing Console and the new Terminal. Further, we realized that this would allow us to build much of the Terminal's core itself as a reusable UI control that others can incorporate into their own applications.
The result of this work is contained within this repo and delivered as the Windows Terminal application you can download from the Microsoft Store, or directly from this repo's releases.
Resources
For more information about Windows Terminal, you may find some of these resources useful and interesting:
- Command-Line Blog
- Command-Line Backgrounder Blog Series
- Windows Terminal Launch: Terminal "Sizzle Video"
- Windows Terminal Launch: Build 2019 Session
- Run As Radio: Show 645 - Windows Terminal with Richard Turner
- Azure Devops Podcast: Episode 54 - Kayla Cinnamon and Rich Turner on DevOps on the Windows Terminal
- Microsoft Ignite 2019 Session: The Modern Windows Command Line: Windows Terminal - BRK3321
FAQ
I built and ran the new Terminal, but it looks just like the old console
Cause: You're launching the incorrect solution in Visual Studio.
Solution: Make sure you're building & deploying the CascadiaPackage project in Visual Studio.
⚠ Note:
OpenConsole.exeis just a locally-builtconhost.exe, the classic Windows Console that hosts Windows' command-line infrastructure. OpenConsole is used by Windows Terminal to connect to and communicate with command-line applications (via ConPty).
Documentation
All project documentation is located at aka.ms/terminal-docs. If you would like to contribute to the documentation, please submit a pull request on the Windows Terminal Documentation repo.
Contributing
We are excited to work alongside you, our amazing community, to build and enhance Windows Terminal!
BEFORE you start work on a feature/fix, please read & follow our Contributor's Guide to help avoid any wasted or duplicate effort.
Communicating with the Team
The easiest way to communicate with the team is via GitHub issues.
Please file new issues, feature requests and suggestions, but DO search for similar open/closed pre-existing issues before creating a new issue.
If you would like to ask a question that you feel doesn't warrant an issue (yet), please reach out to us via Twitter:
- Kayla Cinnamon, Program Manager: @cinnamon_msft
- Dustin Howett, Engineering Lead: @dhowett
- Michael Niksa, Senior Developer: @michaelniksa
- Mike Griese, Developer: @zadjii
- Carlos Zamora, Developer: @cazamor_msft
- Leon Liang, Developer: @leonmsft
Developer Guidance
Prerequisites
- You must be running Windows 1903 (build >= 10.0.18362.0) or later to run Windows Terminal
- You must enable Developer Mode in the Windows Settings app to locally install and run Windows Terminal
- You must have the Windows 10 1903 SDK installed
- You must have at least VS 2019 installed
- You must install the following Workloads via the VS Installer. Note: Opening the solution in VS 2019 will prompt you to install missing components automatically:
- Desktop Development with C++
- Universal Windows Platform Development
- The following Individual Components
- C++ (v142) Universal Windows Platform Tools
Building the Code
This repository uses git submodules for some of its dependencies. To make sure submodules are restored or updated, be sure to run the following prior to building:
git submodule update --init --recursive
OpenConsole.sln may be built from within Visual Studio or from the command-line using a set of convenience scripts & tools in the /tools directory:
Building in PowerShell
Import-Module .\tools\OpenConsole.psm1
Set-MsBuildDevEnvironment
Invoke-OpenConsoleBuild
Building in Cmd
.\tools\razzle.cmd
bcz
Running & Debugging
To debug the Windows Terminal in VS, right click on CascadiaPackage (in the Solution Explorer) and go to properties. In the Debug menu, change "Application process" and "Background task process" to "Native Only".
You should then be able to build & debug the Terminal project by hitting F5.
👉 You will not be able to launch the Terminal directly by running the WindowsTerminal.exe. For more details on why, see #926, #4043
Coding Guidance
Please review these brief docs below about our coding practices.
👉 If you find something missing from these docs, feel free to contribute to any of our documentation files anywhere in the repository (or write some new ones!)
This is a work in progress as we learn what we'll need to provide people in order to be effective contributors to our project.
- Coding Style
- Code Organization
- Exceptions in our legacy codebase
- Helpful smart pointers and macros for interfacing with Windows in WIL
Code of Conduct
This project has adopted the Microsoft Open Source Code of Conduct. For more information see the Code of Conduct FAQ or contact opencode@microsoft.com with any additional questions or comments.